In an effort to obtain adequate sealing in an environment where the mandrel for a packer or hanger or other annular seal is to be expanded, there have been a variety of approaches. Some adopt an internally tapered wedge ring that is expanded under compressive stress with a wedge that is driven into it. The ring grows in diameter but its exterior configuration remains the same and the sealing element and spikes extending from the ring move into contact with the surrounding tubular to resist seal extrusion. This design is illustrated in U.S. Pat. No. 7,784,797.
Other designs simply push out a short segment of a tubular string that has a seal and extrusion barriers above and below as shown in U.S. Pat. No. 6,959,759 FIGS. 1 and 2.
Other designs combine expansion with external energizing the sealing element, such as U.S. Pat. No. 6,854,522 FIGS. 17-19.
Ring or spike type extending members that retain the seal in place after set by expansion have been used in U.S. Pat. No. 5,511,620 in FIG. 4. More traditional type of end extrusion barriers that are not in the context of mandrel expansion are located at ends of a compression set sealing element as in U.S. Pat. Nos. 5,215,145 and 5,961,123.
US Publication 2010/0314130 shows in FIGS. 3 and 4 the use of internal inserts 40 somehow assembled in a tubular that is to be expanded only in the regions where there are external seals 34 in a recess built into the wall 36. The swage is somehow mounted in the lower end of the tubular with the swage outside diameter about equal to the drift diameter of the tubular as shown at the bottom of FIG. 3. How the inserts 40 are installed and firmly held in place is not discussed. After expansion the entire pipe has the drift of the expander 46 but only segments of the pipe have been expanded and the initial drift of the pipe has not increased because of the presence of the rings 40 being used under the seals 34 assuming the same drift as the rest of the pipe that is not expanded.
The present invention expands the tubular to increase its drift while the initial exterior recess that hold the seal material are expanded into alignment with the new dimension of the tubular. Rings or spikes that extend generally radially from the recesses before the expansion move radially outwardly with the seal and can penetrate the seal on the way to making contact with the surrounding tubular. The rings or spikes function as extrusion barriers under differential pressure loading after expansion. The rings or spikes can also penetrate the wall of the surrounding tubular for metal to metal sealing or for fixation of the assembly due to the wall penetration of the surrounding tubular. Those skilled in the art will better appreciate additional aspects of the invention from a review of the detailed description of the preferred embodiment and the associated drawings while appreciating that the full scope of the invention is to be determined from the appended claims.